Latch and extractor for electronic module

ABSTRACT

An electronic module for mounting on a base includes a module body and a latch extractor assembly having a metal latch member with a spring arm, a shift member and a latch, and an extractor engageable with the shift member for movement of the latch out of engagement with the base.

FIELD OF THE INVENTION

The field of the invention relates to an electronic module which isremovably mounted on a base. During mounting, the module is latched tothe base and electrical connections are established between anelectronic component in the module and the base.

BRIEF SUMMARY OF THE INVENTION

The invention is an improved latch and extractor for removably mountingan electronic module on a base. The latch and extractor includes springlatches which engage the base when the module is pushed into the base.The module is easily unlatched and removed from the base by pullingupwardly on opposed grip elements to unlatch the module from the base.The module is unlatched by short initial upward movement of the gripelements relative to the module. After unlatching, further upwardmovement of the grip elements removes the module from the base. Afterremoval of the module, the grip elements automatically return to theirinitial positions.

The grip elements are on extractors which engage latch members holdingthe module on the base. The latch members have stiff shift member lowerends. The shift members transmit unlatching forces from the extractorsto the latch arms engaging the base without bending to shift the armsfrom latched positions to unlatched positions in response to smallinitial upward movement of the grip elements. The shift members arechannel-shaped and transmit unlatching forces without bending.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an electronic module mounted on a base;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a vertical sectional view taken along through one side of themodule illustrating a latch and extractor assembly in the latchedposition;

FIG. 4 is like FIG. 3 with the assembly in the unlatched position;

FIG. 5 is an exploded view of the module;

FIGS. 6 and 7 are enlarged views of portions of FIGS. 4 and 5 showingthe latched and unlatched positions of the assembly;

FIG. 8 is a sectional view along line 8-8 of FIG. 4;

FIG. 9 is a sectional view through the module along line 9-9 of FIG. 7;

FIGS. 10 and 11 are perspective views of both sides of an extractor; and

FIGS. 12 and 13 are perspective views of both sides of a latch member.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Electronic module 10 is removably mounted in recess 12 on base 14 whichis typically mounted on DIN rail 16. The module 10 includes body 18formed by two hollow molded plastic shells 20 joined together at acircumferential seam 22 defining a hollow interior cavity 24. Anelectronic component 26 is mounted in cavity 24 and includes anelectrical connector 28 which forms electrical connections with acomplementary electrical connector (not illustrated) positioned in anopening in the bottom of recess 12 when the module is inserted into therecess, as shown in FIG. 1.

Base 14 may be a power supply base for a process fieldbus. Theelectronic component 26 in module 10 may be a power supply device whichregulates the voltage of DC power supplied to a process fieldbusconnected to the base despite variation in the voltage of the powersupplied to the module. Other types of electronic components may bemounted in the module 10. The module may be mounted on other types ofbases.

The module 10 is removably mounted on base 14 by two like latchextractor assemblies 30 located on opposed edges of the module. Eachassembly 30 includes a molded plastic extractor 32, return coil spring34 and metal latch member 36. Each extractor 32, shown in FIGS. 10 and11, includes an elongate strip body 38 extending between grip element 40on one end of the body and cam end 42 on the opposite end of the body.The grip element 40 extends out from one side of body 38 and includes anumber of closely spaced grip edges or corners 44 extending along adiagonal side of the grip element. The edges 44 face down toward recess12 and facilitate manual engagement of the elements 40 and moving of theextractors 32 away from recess 12 to unlatch and remove the module frombase 14, as described below.

Spring pocket 46 is provided on strip body 38. When assemblies 30 aremounted in module 10, grip elements 40 extend outwardly from the edgesof the module and pockets 46 extend inwardly toward the interior of themodule. The recesses in spring pockets 46 face the upper ends of stripbodies 38 and grip elements 40.

Latch member 36, shown in FIGS. 12 and 13, is formed from flat,uniform-thickness strip metal and includes an elongate, tapered-widthspring arm 48, a channel-shaped shift member 50 at the narrow lower endof arm 48 and a mounting member 52 at the wide upper end of arm 48. Thewidth of arm 48 is tapered to reduce stress concentration. Mountingmember 52 includes pairs of mounting ribs 54 extending to either side ofspring arm 48.

Stiff channel-shaped shift member 50 includes a flat base 56 forming anextension of spring arm 48 and opposed sidewalls 58 bent up 90 degreesto base 56 and extending upwardly from one side of the base. Angledfollower arms 60 extend above sidewalls 58 and are adjacent spring arm48. Angled latch arms 62 extend above sides 58 and are on the end ofshift member 50 away from arm 48. The angled edges of arms 60 and 62face down, away from spring arm 48.

Latching surfaces 64 on arms 62 face up toward spring arm 48 and areundercut to improve latching engagement with complementary, angled latchsurface 66 on an inner side of base wall 74 at the bottom of recess 12,as shown in FIG. 6.

The two latch extractor assemblies 30 are identical. Each assembly ismounted on one edge of module body 18. Mounting of an assembly 30 on theright edge of the module shown in FIG. 3 will now be described, it beingunderstood that the latch extractor assembly on the left edge of themodule is similarly mounted on the module.

Latch member 36 is positioned in one open shell 20 by extending themounting ribs 54 on one side of member 36 into recesses 70 in the shellwith the arm 48 and shift member 50 extending freely in an interiorchannel 72 in the shell 20. See FIG. 8. The free end of shift member 50and latch arms 62 extend through opening 76 in module bottom wall 79.The adjacent faces of the pairs of ribs 54 in recesses 70 have tightfits with the adjacent walls of recesses 70 to locate member 36accurately in channel 72.

Extractor 32 is fitted in an elongate groove 78 extending along the sideof the shell 20 holding the latch member 36. Strip body 38 is freelymovable along the groove. Spring pocket 46 extends into recess 80 formedon the inner side of groove 78 with compressed spring 34 extending fromthe bottom of the pocket to the slotted upper wall 82 of the recess.Wall 82 is slotted to accommodate a tool holding spring 34 compressed inpocket 46 during installation of the extractor and spring into thegroove 78 and recess 80. Groove 78 extends from wall 79 at the lower endof the shell to step 84 adjacent the upper end of the shell. Spring 34normally holds extractor 32 in a down position, shown in FIG. 3, withthe lower end 81 of the extractor on wall 79. See FIG. 6. Grip element40 is normally located immediately above step 84 when extractor 32 isheld in the down position shown in FIG. 3 by spring 34.

With the extractors 32 and metal latch members 36 positioned in oneshell, and electronic component 26 and connector 28 positioned in theshell, the second shell is positioned over the first shell, and the twoshells are moved together so that the adjacent edges of the shells abuteach other. The shells include post and recess latches on their abuttingedges. The latches secure the two shells together to form body 18 withthe latch extractor assemblies, electronic component and connector heldin place in body 18.

The cam end 42 of each extractor 32 has two angled cam surfaces 86.Surfaces 86 are on opposed sides of cam end 42. When grip elements 40are pulled up, the cam surfaces 86 immediately engage angled followerarms 60 on the sidewalls 58 of shift members to immediately flex theadjacent spring arms 48 inwardly and move members 50 from latchedpositions adjacent the outer side of the module, shown in FIGS. 3 and 6,to unlatched positions inwardly from the outer edges of the module,shown in FIGS. 4 and 7. Springs 34 are compressed and ends 81 are raisedabove wall 79. Spring arms 48 bias the channel members toward thelatched position. Upward movement of grip elements 40 short distance 75,shown in FIG. 4, moves cam ends 42 into engagement with shift members 50to cam members 50 laterally inwardly, away from the adjacent sides ofthe module, to the unlatched or released position shown in FIGS. 4 and7.

Assembled module 10 is latched into base 14 by extending the lower endof the module into recess 12. Lead ends 92 of shift members 50 arepiloted into latch openings 68 formed through base wall 74. The angledsurfaces of latch arms 62 engage the outer edges of openings 68 so thatthe members 50 are moved inwardly and arms 48 are flexed inwardly inchannels 72 until arms 62 pass through the openings 68 and the flexedspring arms 48 move outwardly to move the latch arms 62 outwardly andunder latch surfaces 66 to the latched position shown in FIGS. 3 and 6.During latching of the module onto the base, the top of the module ispushed into the recess. Connector 28 engages the connector on base 14.The arms 48 are flexed to move shift members 50 through openings 68 andto the latched positions. The extractors 32 are not used to latch themodule to the base.

In order to remove a latched module from the base, an operator pulls theundersurfaces of grip elements 40 up a short distance 75 away from base14. The edges 44 improve the operator's grip of elements 40. The initialupward movement of the grip elements 40 pulls cam ends 42 up from theposition of FIG. 6 to the position of FIG. 7. Cam surfaces 86 on theopposite edges of cam ends 42 are brought immediately into engagementwith the angled follower surfaces on arms 60 located on the outer sidesof the upper end of shift member 50. Cam ends 42 are supported againstoutward movement by raised pads 88 which are located centrally on theends, equidistant between the two cam surfaces 86. Upward movement ofcam ends 42 rotates shift member 50 inwardly and flexes spring arm 48inwardly to move latch arms 62 inwardly a distance beyond latch surface66 to unlatch the module from the base.

Upward movement of grip elements 40 simultaneously unlatches the twomembers 50 from base bottom wall 74 and, with further upward movement,withdraws the unlatched module from the base recess and disengages theconnectors.

During unlatching of the module, pads 88 on cam ends 42 engage the outerwalls of grooves 78. The pads 88 are located between the two laterallyspaced cam surfaces 86, in the center of cam end 42, to support thesurfaces during inward camming of shift members 50 and prevent twistingof ends 42 and members 50. The pads 88 also space the outer surfaces 98of strip bodies 38 from the adjacent walls of grooves 78 to reducefriction during unlatching.

Metal shift member 50, with flat base 56 and upstanding channelsidewalls 58 has a channel-shaped cross-section and is very stiff. Thestiffness of the member prevents bending of the member during unlatchingwhen forces exerted by the cam end 42 of extractor 32 on the spacedfollower arms 60 are transmitted along the length of the member 50 tomove latch arms 62 on the bottom of the channel member inwardly andunlatch the module. During unlatching each member 50 directly transmitsunlatching forces along each L-shaped sidewall of member 50 from an arm60 to an arm 62 to move arms 62 inwardly away from the angled latchsurfaces 66 on the bottom of the base without bending. The lateralstiffness of the channel-shaped metal shift member 50 assures that themember is not deformed laterally despite location of arms 60 outside ofpad 88.

The cam end 42 of extractor 32 and shift member 50 of latch member 36are fitted together in alignment with follower arms 60 on member 50extending into recesses 100 formed in the sides of cam end 42.

What we claim as our invention is:
 1. An electronic module comprising amodule body and a first latch extractor assembly for removably mountingthe module body on a support member, the latch extractor assemblyincluding a metal latch member having an elongate spring arm, a mountingportion at one end of the spring arm, and a shift member at the otherend of the spring arm, said mounting portion secured to the module body,the shift member including a generally flat base and a first basesidewall extending up from the base at an angle of about 90 degrees sothat the shift member is L-shaped and rigid, a first latch arm on thefirst base sidewall away from the spring arm, a first follower arm onthe first base sidewall adjacent the spring arm; and an extractor havingan elongate extractor body, a grip element at one end of the extractorbody and a first cam surface at the other end of the extractor body, thecam surface engaging the first follower arm; whereby movement of thegrip element moves the cam surface along the follower arm to cam theshift member laterally and move the latch arm out of engagement with asupport member, the shift member transmitting forces from the followerarm to the latch arm without bending.
 2. The module as in claim 1including a spring biasing the extractor to move the cam surface awayfrom the follower arm.
 3. The module as in claim 1 wherein the springarm is flat and tapered.
 4. The module as in claim 3 wherein said baseforms extension of said spring arm.
 5. The module as in claim 1 whereinthe shift member includes a second base sidewall, a second latch arm onthe second base sidewall and a second follower arm on the second basesidewall; and the extractor includes a second cam surface engageablewith the second follower arm.
 6. The module as in claim 5 wherein saidshift member is channel-shaped.
 7. The module as in claim 1 wherein thelatch extractor assembly is located on a first module edge.
 8. Themodule as in claim 7 including a second latch extractor assembly locatedon a second module edge.
 9. The module as in claim 1 wherein the firstlatch arm is located outside the module and the first follower arm andthe cam surface are located inside the module.
 10. The module as inclaim 1 wherein the extractor body extends to one side of said springarm and is located between the spring arm and the outer surface of themodule, and the grip element is located on the outside of the modulebody above the metal latch member.
 11. The module as in claim 1 whereinthe shift member includes a second base sidewall and a second followerarm on said second base sidewall; and the extractor includes a secondcam surface engageable with the second follower arm.
 12. The module asin claim 11 wherein the extractor includes a pad located away from theshift member, the pad between the first and second cam surfaces, saidpad engaging a surface of the module, wherein the pad spaces theextractor body from the module to reduce friction and support the shiftmember.
 13. The module as in claim 12 wherein the shift member includesa recess adjacent each cam surface, the follower arms extending intosaid recesses.
 14. The module as in claim 1 including an electroniccomponent in the module body and an electrical connector attached to thecomponent for forming electrical connections with a complementaryelectrical connector.
 15. The module as in claim 14 wherein saidelectronic component comprises a power supply device for regulating thevoltage of DC power supplied to a process fieldbus.
 16. An electronicmodule comprising a module body, a power supply device for regulatingthe voltage of DC power supplied to a process fieldbus, an electricalconnector joined to the power supply device, the power supply devicemounted in the body; a first latch extractor assembly for removablymounting the module on a power supply base for a process fieldbus, thelatch extractor assembly including a metal latch member having anelongate spring arm, a mounting portion at one end of the spring arm anda shift member at the other end of the spring arm, said mounting portionsecured to the module body, the shift member adjacent the power supplybase and including a shift member base, first and second base sidewallsextending up from opposed sides of the base at about 90 degrees so thatthe shift member is generally channel-shaped, first and second latcharms on the base sides away from the spring arm, first and secondfollower arms on each base sidewall adjacent the spring arm; and anextractor having an elongate extractor body, a grip element at one endof the extractor body away from the power supply base and first andsecond cam surfaces on the other end of the extractor body adjacent theshift member, the cam surfaces engaging the follower arms; wherebymovement of the grip element moves the cam surfaces along the followerarms to cam the shift member laterally and move the latch arms out ofengagement with a power supply base, the shift member transmittingforces from the follower arms to the latch arms without bending.
 17. Themodule as in claim 16 including a pad on the extractor between the samecam surfaces and away from the shift member, the pad engaging a surfaceof the module to space the extractor body from the module and supportthe shift member.
 18. The module as in claim 16 wherein the latch armsare located outside the module.
 19. The module as in claim 16 includinga spring mounted between the module body and the extractor, such springbiasing the cam surfaces away from the follower arms.